‘A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.’

You can connect to the subscriber from Management Studio and query the subscription database but the Distribution Agent still fails with connection errors.

Cause

Distribution Agent fails to connect if the 64-bit alias for the subscriber server is missing at the publisher/distributor server. SQL Server Management Studio is running in 32 bit mode will use the (32bit) alias.